Can I be blacklisted at a company if I withdraw my acceptance to a job offer?

I'm currently unemployed and in between jobs. During the past month, I've been interviewing at two companies (let's call them 1 and 2). I like company 2 better but they were moving much slower in the interview process than company 1. After I had my 4th round with company 2, company 1 contacted me about a week later and offered me the job. During that week, I tried contacting company 2 to follow-up and see if they made their decision but HR never got back to me. So I really thought that I didn't get the job and decided to take company 1's offer. However, yesterday company 2 contacted me and said they would like to move forward with an offer. Now I don't know what to do since I already accepted company 1's offer. Would it be bad if I backed out of the offer and would I be blacklisted? I just want to make the right choice. Please help

yes, i did send in my tax forms, personal profile and direct deposit form to HR. i don't know if this changes anything?

This happens all the time. Companies get mad, but they also get over it.

The answer to your question does depend on what level job it is. If you were interviewing to be CEO, for instance, of Company 1 & Company 2, then yes once you reject them you won't be asked again. But if it's to get a relatively high turnover kind of job (like now you're interviewing for counter jobs at McDonalds vs. BKing), where they're recruiting all the time, then no they normally won't notice.

Whatever job you're going for, it's probably somewhere in the middle. Apply common sense. Treat your contact at each company in the way that you'd want to be treated. Don't lie to them. Don't blattenly flatter them, and don't insult them. Don't be overly emotional about it -- either way, the decision probably means a lot more to you than it does to them. Both parties to a transaction like this are shoppers, and you both need to make the right decision for you.

As long as you haven't started work you can probably back out with minimal fuss. They won't like it, but generally won't have a written blacklist or anything. I wouldn't apply with them while the people you dealt with are still there, though as they won't be happy.
Now morally, what is your position. Have you signed an agreement? Did they make you a written offer and did you accept in writing? Have you set a date for starting? Have you started?. Did you orally accept an offer? Have you filled out any paperwork as an employee?
Legal and moral are frequently not exactly the same.

Yes some companies do blackllist people, but if you're upfront with them, they should be ok with it and depending on what your skill set is and how bad they need you they might match the offer. Try never to burn a bridge, you never know when you might need to cross that way again.

If you have not yet started the job at company 1, then I would go ahead and accept the job at company 2 and politely tell the people at company 1 that you received job offer that affords you more opportunity, better pay, better benefits, etc. (even if that is not necessarily the truth, it will be OK this one time to say any one or more of those things). You should also tell them how very grateful you are for the job offer and hope that this decision does not put them in a bind.

The bottom line is that if you REALLY think there is a difference in the two jobs and you are SURE that job 2 is the one for you, then take it. Don't take the one you want least and have regrets later. There will be plenty of time for regrets all throughout the rest of your life.

Good Luck.